I would like to build an overdrive unit that only utilizes an op amp and a voltage divider circuit to bias the op amp (using only one power supply).
I do not want to get into any diode clipping, for now. I just want to build a basic op amp based circuit.
Does anyone have such a schematic that I can base this on? I have the following op amps:
TL082. 4558D. and UA741CP
Thanks a lot.
As a footnote, I tried building full overdrive pedals including diodes, but I have never succeeded in getting it to work. So, I'd like to start small and just master a simple op amp circuit before going any further.
Thank-you
If you don't want diode clipping I think yuo should use the inverting input of the op-amp.
Something like the Mockman 2.0 by ROG? I have just this in mynd. It's pretty high gain, but I think you can limit the gain in the first stage.
http://www.runoffgroove.com/mm2.html
A modified Guv' nor ..
(https://i.imgur.com/uc3BrcY.jpg)
Quote from: Guitarist335 on May 24, 2021, 12:13:21 AM
As a footnote, I tried building full overdrive pedals including diodes, but I have never succeeded in getting it to work. So, I'd like to start small and just master a simple op amp circuit before going any further.
The diodes by themself woudn't make the effect to not work. It was something else. I suggest you to do a simple build but still keep the diodes, there are very simple circuits using them.
For example, this one, for a breadboard:
https://www.diystompboxes.com/smfforum/index.php?board=33.0
Or this one, which is a simpler Tube Screamer:
http://www.runoffgroove.com/tubereamer.html
You can start a topic on the "building your own stompboxes section", posting your steps as you're doing them, and we can help in case something goes wrong.
Quote from: Marcos - Munky on May 24, 2021, 08:57:45 AM
Quote from: Guitarist335 on May 24, 2021, 12:13:21 AM
As a footnote, I tried building full overdrive pedals including diodes, but I have never succeeded in getting it to work. So, I'd like to start small and just master a simple op amp circuit before going any further.
The diodes by themself woudn't make the effect to not work. It was something else. I suggest you to do a simple build but still keep the diodes, there are very simple circuits using them.
[...]
Or this one, which is a simpler Tube Screamer:
http://www.runoffgroove.com/tubereamer.html
I'm agree. I didn't read the reason you didn't want diodes. I built a MXR MicroAmp and a DOD 250, similar schematic, different values, but the DOD 250 has the a pair of diodes, it wasn't harder to build it just for that.
A Tube Reamer is ok for me, too. Simple and well known schematic.
If you like it, the Red Llama, it has no diodes, is simple enough, too.
If it is a 2-stage effect, such as the Guvnor - you can test the first stage before you assemble the 2nd! :) This will help isolate where a problem may occur later in the build.
Thanks for all the advice. Much appreciated